Valve mechanism for servo-motors



De@ my H935.. c. A. BUTLER VALVE MECHANISM FOR SERVO MOTORS Filed Feb. 25, 1955 2 Sheets-Sheet 1 c. A. BUTLER VALVE MECHANISM FOR SERVO MOTORS Filed Feb. 25, 195s Cil Patented Dec. 10, 1935 UNITED OFF ICE deceased Application February les, 1933, serial No. '658,199

`8 Claims.

This invention relates to improvements in pneumatically actuatedpumping systems of the type described in :my prior 4Patent No. 1,839,140, v4and in my copending applications Serial Nos. 602,348 and 602,349, filed March 31, -1-932, and more particularly relates to improvements in :the assemblage of such units.

One of the features of the .present invention is the construction of a servo vmotor structure in which reciprocating valves of the needle type are employed `for controlling the actuation ofthe servo motor piston.

lAnother feature of the present invention isthe provision of a mechanism `for actuating such .reciprocating valves by which the inlet and exhaust from the opposite ends of the servo motor cylinder are positively controlled, and means are provided for holding the valves in y'opened or closed position.

A further feature of the invention is the-provision of such a valve-controlled system, including two pairs of valves with means for balancing the efforts upon the valves while permitting them to be rmly seated for obstructing their cor-responding passages.

Still another feature of the invention Vis the provision of sealing means at the ends of the cylinder for cooperation with the faces of the piston in securing tightness against leakage around the piston while the latter is at its ends-of travel.

A still further feature of the present invention is the provision of a servo motor controlled system which is not subject to derangement or improper opoeration by reason of sudden air movements within the pump structure.

With these and other objects in view, as will appear in the course of the following specification and claims, an illustrative form of practicing the invention is set forth on the accompanying drawings, in which:

Figure 1a is a fragmentary upright sectional View substantially on line la-la of Figure 2.

Figure 1b is a similar View substantially on line lli-Ib of Figure 3.

Figure Ic is a view corresponding to that of 1b, but showing the lower portion of the general-casmg.

Figure 2 is a horizontal sectional View, substantially on line 2 2 of Figure 1a.

Figure 3 is a horizontal sectional view substantially at line 3 3 of Figure 1b.

Figure'll is an upright sectional view, on a larger scale, of the servo motor and its control system, being in section substantially on lines 4 4 of -Figures 5 and 9.

(o1. A-izi--szin -Figure 5 .fis an upright sectional view substantially online V5 5 of Figure 4.

Figure 6 is a fragmentary upright lsectional View substantially on lines 6 6 of Figures '7 and 9.

Figures FZ, 8 and 9 yare horizontal sectional views 5 through the .servo motor substantially on -lines 1 1, 8 8'and 9 9 of Figure 4.

Figure 10 is a detail of the valvepivot arrangement, on a larger scale than that of Figure 5.

AFigure V1,1 is a :perspective View of the valvejacm tuator rocker-piece.

,Figure 12 is a view corresponding to a portion of Figure 4, but show-ing the valve actuating and controlling elements ina different position.

In these drawings, a single unit for a pumping T5 system is set out for operation as described in my aforesaid Patent 1,889,140, and yin the copendi-ng applications. -In the patent and appl-ications `an air pressure pipe is carried ,from the ground level, for instance, downwardly in an oil 2O well casi-ngto the lowermost pumping unit, and is Yprovided with branch connections to each individual unit. In operation the air Apressure is initially automatically shut olf from the lowermostunit and this unit is permittedtovll with oil. When this lowermost unit -is full, a 'float'is raised Vand thereby thecontrol valves of a servo motor are actuated to cause a movement of the servo ymoto-r VKpiston vand `thus an opening of Athe branch 4connection to this air pressure pipe. At 30 the same time, anair exhaust from this unit is closed. The entering air under pressure thus operatesgtoforce the oil from thisunit upwardly through-an oil delivery pipe to a next higher unit. The units are constructed similarly and thus operatein cascade to leffect a raising of the oil by eac-h :success-ive unit until it is delivered at the groundflevel. A more `detailed descriptionof this opera-tion'by several units is contained in my aforesaid :patentand the employment of such a 40 plurality 'of units 'in cascade `is not claimed in the present application. Y

The .presentapplication is concerned with the construction `of a unit for employment in such a System. Y

The structure is set out on the accompanying drawings as 'including an air connection and exhaust system 'of the type described, shown and claimed -in ythe aforesaid copending application Serial No.- 602,349. According to such an arrangementa conduit l0 for gas under pressure is led downward to `rand through the unit, if it be other than the bottomunit, 'so that the conduit I l) supplies the -gas under A.pressure to all of the units.

At apoint above the unit. the Vpipe lll has a 55- branch IIS communicating with the branch conduit I3 through which air may pass to a back pressure valve |26 and thus through the passage 'i in the upper closing plug I3 to the air inlet valve 45 of the unit. Likewise, the upper closing plug I8 has a passage 26 therein for establishing communication from the exhaust valve 32 to the exhaust pipe 26a which extends upwardly from the closing plug IS any desired distance, and is preferably provided at its upper end with a check valve structure |3'Ib which will prevent the downward movement of iiuid in the exhaust pipe 26a.

Likewise, the unit is shown as including a casing I8 having a bottom closing plug 22 through which the pressure-gas conduit I may extend, and to which is led the supply conduit |2 by which liquid may enter the unit. The inlet pipe I2 is in communication with the body 92 of a check valve structure having a valve body S3 to prevent the reflux of liquid from the unit. A liquid discharge pipe I8 is located within the unit and is provided at its lower end with a check valve 8E which prevents the return of liquid from pipe 78 into the unit. The pipe '.'8 extends upwardly and communicates through the upper closing plug I8 with a liquid discharge line as described in my aforesaid patent and applications.

The gas inlet and outlet valves 45 and 32 are connected to corresponding slide blocks 44 and 3| which may be moved by the lever 6l which is pivotally mounted on the axially movable rod 65. This rod 65 is pivoted at its lower end to a lever 39 which is supported by a fixed pivot 40 on a fixed bar 4I, at one end, and is connected by pivot 33 at the other end to the piston rod 31 of a servo motor structure. When the piston rod 38 is in raised position, the inlet valve 45 is open and the exhaust valve is closed: and vice versa when the piston rod 3'I is in a lower position, the inlet valve 45 is closed and the exhaust valve 32 is open.

Within the housing I9 is provided a float II which is raised by the liquid when the latter has attained a predetermined level in the housing I9, and thus operates to raise a lever 54 which is supported on a fixed rod 68 and is pivotally connected to a servo motor actuating link 53, 5312, whereby it operates to move a lever arm 52 and thus, in a manner described hereinafter, to cause a movement of the servo motor parts including the piston rod 3'I whereby to raise the rod 65 and thus move the valves into the position shown in Figure la,

Further, the casing is provided with a bucket I4 which is in part counter-balanced by a spring 82 so that it rises when the liquid level is above its top: but so that its contents of liquid will cause it to drop as the liquid level retreats, and thus ultimately depress a lever 69 which is pivotally mounted on a rod "I2 and thus operate to draw the servo motor control link 53h, 53 down again. The bucket 'I4 is preferably mounted within a shield '15. 'Ihe spring 82 and the shield 'I5 are supported by brackets 11 connected to the pipes I8, 'I8 within the housing I9. A buffer 8Ia is likewise supported by a bracket 8| in similar manner, and serves to receive the float at the end of the downward movement of the latter. The inlet of gas under pressure to the servo motor is accomplished through a branch connection |30 from branch conduit I3, by a pipe 6I: while the exhaust from the servo motor is accomplished through a pipe 5S and its extension 59a which leads to a check valve |31, having the same general height above the upper closing head or plug I8 and the same function as the check valve |3Ib.

These parts are disclosed, with the same reference numerals, in my aforesaid copending application Serial No. 602,349, and are referred to in the present application to show the relationship of the structure here described to these prior devices.

The hollow structure 3U in which is provided the seat for the exhaust valve 32 and a sliding support for the valve block 3|, serves in the present illustration also to support the threaded end I4!) of a block IliI which has spaced downwardly extending arms |42 secured thereto. These arms I 42 are connected, as by welding, at their lower ends to a block |43 providing the fixed body of the servo motor structure. The

lower part of this body has a cavity |44 constituting a cylinder. The lower end of the cylinder is closed by a screw plug |45 through which the piston rod 37 passes, with the employment of a tight packing |46. The upper end of the piston rod 31 is reduced and receivesl against its shoulder the rabbetted disk |47, the flat disk |48 and the threaded and rabbetted nut member I 49. These three members have substantially the same diameter and provide a piston structure in conjunction with the piston rings |50 located in the rabbet grooves. The upper end of the cylinder I 44 has an annular groove in which is received a sealing ring IiI which may be of rubber or like material for cooperation with the upper surface of the closing nut |49 when the latter is in its uppermost position, so that the tightness of the piston, in this end position, does not depend wholly upon the piston rings I 50.

Similarly, the plug is rabbetted at its upper end to receive a sealing ring |52.

Four parallel holes are provided in the upper end of the servo motor body, the axes of these holes being parallel to the axis of cylin er |44 and piston rod 3'I in the illustrated forin. Each of these holes is intended to receive a longitudinally movable needle vaive, and is closed at its upper end by a packing |53 for preventing the escape of compressed gas along the length of the needle valve. These needle valves are arranged in pairs, comprising an inlet valve iE-'la and an outlet valve Ib for the lower end of the cylinder, and an inlet valve IE/lc and an outlet valve I54d for the upper end of the cylinder. Each of the aforesaid holes has a large diameter down to the two diagonally extending passages E53, |35 which are respectively in communication (Figs. 5, 8 and 9) with the corresponding exhaust and inlet conduits 59 and 5|. Thus, the inlet valves a and |530 control the movement of compressed gas from the passage ii, while the valves 954i) and Iid control the movement toward the exhaust passage |59.

The aforesaid four bore holes are smaller at their lower ends, below the diagonal passages I 59 and SI which intersect therewith, and their walls adjacent such diagonal passages provide seats for the lower ends of the said valves. The bore hole I55a corresponding to valve |54a. leads into a cross-communicating passage |56 and thence to a longitudinal passage |57 downwardly along the cylinder |44, with communication through an opening |58 with a peripheral groove |45a in the lower closing plug |45, and this groove in turn communicates by openings |451) with the internal space ci cylinder |44. Into the cross passage |55a1s`oopens the holeA |551) corresponding to the valve |5417. The'holes |550 and |55tt`- are shownin this form as Acommunicating directly with the upper end of theA space ofA cylinder |414.

The lever 52is shown in Figures 4 and frtdbe doubled in' structure, and to have upwardly extending arins 52a integral therewith, these' arms being connected to a block |62 providing a rest for a knife edge |55 secured at the lower endv of a plunger having a collar |64" which is'forced downwardly by a spring |55 resting at its upper end againstl the bottom of a Vcavity in a4 toggle cap |56 which has apoint Hita resting in a depression |61 in the block IM. The upper ends of arms 52a are preferably provided with spaced points (Fig. 4) between which is received the knife edge |53, which for its part has downwardly extending portions at itsr ends for preventing translational movement of the knife edge inthe direction of its length.

The lever 52 is connected by a pivot 15 with a valve member 1| which supports pivot rods |12' for the links |13 which in turn are connected by pivots |14 with the upper ends of the needle valves i54a, |542), |54c and |54d. This valve'actuating member IH is constructed as shown in Figure 11,

of sheet metal folded to provide four spaced' parallel legs |'1|a, the gap between the two center legs being closed by a piece |1|b welded thereto, and the free ends of the original strip are likewise joined by welding, so that a strong composite structure is produced. The outer walls are closely received between the straps |42, while the portions of lever 52 t just outside the two inner' walls, and the links |13 are received between the two inner walls. Extending through apertures of all these walls is the supporting pivot |16 which preferably has an upward extension |11 forlimiting axial movement. The apertures through which the pivot E15 passes, in the walls ITI'a, are oblong, with their major axes in the plane through the axis of pivot |19. This permits movement of the member |1| relative to this supporting pin |15, for self -adjustment Further, the pivots |14 (Fig. 10) at the lower end of each link |15 preferably pass through apertures in linksl |13 which are belled-out at each end, whereby the `pins |14 may rock, and

thus assure correct seating of the corresponding surfaces (Fig. e) of member I1 andthe connecting wall 52h likewise can make a slight clockwise movement with lever 52 relatively about pivot |18 before it encounters member It will be noted that the several passages may be formed easily by drilling in the body |43, and then closed by corresponding plugs |559; |5932, llx (Figs. 7, 8 and 9).

In operation, when the parts are in the position of Figure la, compressed gas is entering past the open inlet valve 45, and by its action upon the body of liquid in casing I9 is forcing this liquid therefrom and through the check valve 85 and pipe 18. At this time the exhaust valve 32 is closed, piston rod 31 is in its raised position, gas inlet needle valve |540@ is open while gas inlet needle Valve i550 is closed, exhaust valve |54d is open while exhaust valve |5412 is closed, so that the lower end of the cylinder |44 has been receiving gas under pressure from pipe 6|, while the upper end'hasbeenexhausting through pipes 59', 59u; The servofm'otor actuating link 53, 53h isin raised position and lever 52 is inrits-extrenie clockwise position of'movement, and the toggle devicesi'2a, ISG'have been displaced: tothe right 5 from the central position of Fig. 4, so that these devieesare holding the valves in such positions.

.lts`A the forcing of liquid from housing |9` continues, the float 1-"I` descends and comes to rest on they bumper Bla, and nally, as the liquid level lo fallsbelow the top of the shield 15, the bucket 14 begins to sink and by its engagement with lever 69 causes af downward movement of the servo motor control link 53, 531), and thus a counterclockwise movement of lever 52. At first, this movement causes a rocking of valve actuating member |1|` to close the open valves |5411, |54d under the action of spring |55 as the toggle devicesswing toward central position, this closing being permitted by the oblong hole for pivot |16. In the course of this movement, however, the knife edge |63 is moved past the line of centers between the .point |656: and the axis ofpivot |10, so that the energy which has been stored in spring |65I during this initial movement is now 25 released and cooperates with the downward pull of link 53, 53h, to cause a further movement of lever 52 and therewith a tilting of the valve actuating member |1| which assures the complete closing of valves |54b and |540 and the opening 30' of valves |`54a and |54d. Thus, the connections to the cylinder are reversed, so that the lower end of the cylinder is permitted to exhaust while compressed gas isV delivered to the upper end. The piston andits rod 31 are thus moved down- 3: ward and cause a reversa of the main valves 32 and 43, thus shutting off the inflow ofcompressed gas into the housing i9, and permitting the latter to exhaust to conduit 25, 26a. Liquid then enters through pipe |2 and past check valve 94, 4() raising the bucket 14 so that lever 69 is free and ultimately raising the float 1| and operating lever 54 to reverse the aforesaid actuation` of lever 52 andi thus return the parts to the initial position. Compressed gas now flows from pipe 6| 45 and passage |6| to the lower end of the cylinder, while the upper end is permitted to exhaust. Thus the servo motor returns the valves 32` and' to the position shown in Figure la, and the device is returned to its former position. The structure thus comprises a casing which may be placed in communication with a compressed gas conduit or with an exhaust conduit by the operation of the main valves 45, 32V.. This operation is secured by a servo motor structure 55 comprising a cylinder and piston, anditself controlled through the agency of the four reciprocating Valves which selectively control the opening and closing of passages leading to the cylinder ends, with respect tocompressed gas and ex- A haust conduits 6|, 59, etc. These valves are controlled by a rocker piece which is in effect a walking beam connected at its ends to the valves, but capable of a vertical bodily movement by reason of the provision of its slots for reception of the pivot |16. The crank lever 52, 52a is pivoted to this rocker piece, but has a certain free movement with respect thereto, so that it accomplishes a positive movement of the rocker piece, which has a limited free movement when its own motion is reversed. This lever is associated in a toggle system whereby the toggle is also available for its normal toggle link purpose of moving the lever toward its end positions and holding it therein, with two of the valves raised and the other two closed. This lever is actuated by the float and bucket which thus constitute means responsive to the liquid level prevailing within the casing. A further feature of the arrangement is that the rocker piece permits differential downward movements of the two valves which are located at each end thereof (Fig. so that the seating of these valves is assured under the action of the aforesaid spring pressure, even tho-ugh the length of each valve is not identical with the length required for accurate closing during the downward movement of the rocker piece.

The violent gas and liquid currents Within the housing tend to move the levers 52 and 54 before the true actuation by the bucket has occurred. For this purpose, baffles i90, i9! are provided above these levers, whereby to avoid such injurious actuation.

It is obvious that the invention is not limited to the form of construction shown, but that it may be modified within many ways of the scope of the appended claims.

Having thus described the invention, what' I claim as new and desire to secure by Letters Patent, is:--

l. In a device of the class described, a valve actuator, supporting means for said actuator, reoiprocable inlet and outlet valves, said valve actuator having pivot connections to each of said valves, a control lever pivoted to the actuator between the Valve pivot independently of said supporting means, means on said lever and actuator for causing positive movement of the actuator by said lever upon motion of the latter in either direction and affording a limited free movement of the lever upon reversal of its direction of movement, and a spring for pressing said lever toward said actuator.

2. A device as in claim 1, including xed pivot means engaged with said actuator for preventing bodily movement of the actuator during the free movement of the lever.

3. A device as in claim 1, in which said actuator is movable in the direction of Valve movement and said spring is included in a toggle link cooperative with said lever actuator and valves for moving all the valves toward closed position and cooperating with said lever to cause movement of the lever toward its end positions and operating to hold the lever in such end position with one valve open and the other closed and also operating to move the actuator and valves bodily toward closed position of the valves.

4. In a device ci the class described, a frame, a rocker piece; a toggle including a spring, a rst toggle link pivotally connected to said piece,

a second toggle link cooperative with said iirst toggle link and having pivotal engagement with said frame; a pair of rectilinearly movable valve means connected to' said rocker piece at opposite sides of the axial plane of said frame pivot engagement which intersects the point of said pivotal connection, a loose pivotal connection between said piece and the frame spaced from said toggle pivot connection and operative for preventing lateral bodily movement of the piece and permitting bodily movement toward and from the point of pivotal engagement of said second toggle link for assuring the seating of at least one said valve means at all times and of both said valve means in the course of the movement of,

the rocker piece, and means for rocking said rst toggle link.

5. A device as in claim 4, in which each valve mea-ns includes a pair of valves and means for pivotally connectinfr the same to said rocker a piece, said pivotally connecting means including loose connections cooperating with said loose pivotal connections for assuring the seating of both valves of a pair by the action of said toggle spring.

6. In a device of the class described, four substantially parallel passages arranged at the corners of a rectangular cross section, inlet and outlet conduits extending across the diagonals of said section and each communicating with two f of said passages, valves for closing the communication between said conduits and passages, a walking beam rocker-piece, said valves being connected to the ends of the walking beam rocker-piece, and spring means cooperative with said i.

rocker-piece for holding said valves closed when said walking beam is in center position and for causing rocking of said walking beam about either end for effecting an opening of the valves connected at the other end thereof.

'7. A device as in claim 6, in which the rockerpiece has a slot therein and a pivot member on said frame passes through the slot, said pivot and the walls of the slot operating to prevent bodily movement of the rocker-piece in the plane of the valve connection.

8. In a device of the class described, a rockerpiece, means providing an axis about which the piece may turn a transverse pin extending through an aperture of the rocker-piece located at a point spaced from the said axis, reciprocable Valves having apertures for the reception of said pin, said apertures having a greater cross sectional area for at least a portion of their length than the cross sectional area of the pin, whereby the pin may rock within said rocker-piece and valves so that a downward movement of the rocker-piece at said pin will produce a positive closing of both said valves.

CHARLES A. BUTLER. 

